Query your fleet with an agent

This guide walks through asking a coding agent about your fleet: installing the upbound-hub skill, letting it sign you in, asking a first question and checking that the answer came from where you think it did.

note

The steps use Claude Code, the supported agent today. See Supported agents for the state of the others.

Prerequisites

• Claude Code, and the tools the skill's scripts call: bash, curl, jq, column and shasum
• The base URL clients use to reach hub-core, the same value as hub-core.api.externalURL
• An account with read access to at least one realm. See Access and authorization
• At least one connected control plane, or the answers have nothing to report on

Step 1: Install the skill

1. Register the marketplace and install the plugin.

   /plugin marketplace add upbound/skills
   /plugin install upbound@upbound

2. Confirm the agent picked up the skill.

   Ask it what skills it has available. upbound-hub should appear, described as the skill for querying and mutating Upbound Hub.

Step 2: Point the skill at your Hub

The skill sets itself up the first time you ask it a fleet question. It installs its credential helper, checks the download against a published SHA-256 and signs you in, so there's no setup command for you to run. All it needs from you is the endpoint and a browser.

1. Ask an ordinary question to trigger setup.

   How many resources are unhealthy across the fleet?

2. Give the agent your Hub API endpoint when it asks.

   The skill has nowhere to discover this on its own, which is why it asks. It saves the value to ${XDG_CONFIG_HOME:-~/.config}/upbound/hub.env and doesn't ask again on this machine.

3. Complete the sign-in in your browser.

   The setup script opens a browser window. Finish the sign-in there and the agent carries on with your question. The credential lasts about 90 days.

Step 3: Read the first answer

Fleet health is the question agents get wrong most often, which makes the first answer a good test of whether the skill loaded. A correct one separates three figures rather than collapsing them into a single percentage:

Figure	What it counts
Assessable	Resources reporting Ready explicitly, either True or False
Failing	Resources where Ready is explicitly False
Not reporting	Resources carrying no conditions, or reporting Unknown

Most records in a fleet land in that last row, which is why an "X% unhealthy" figure divides by a denominator that doesn't mean anything. If your agent answers with one percentage it isn't using the skill, so check that the plugin installed and that upbound-hub loaded for the question you asked.

A fleet-wide answer counts Ready alone, because the aggregation endpoint counts each condition on its own axis and a resource can fail more than one, so the counters overlap and you can't add them up. A per-control-plane answer does treat Synced or Healthy being False as failing, so the two scopes report different totals. Ask which one a number uses.

It helps to remember that Unknown isn't a failure. It's the normal state for the whole window a managed resource takes to come up, and Synced=False with a reason of ReconcilePaused means someone chose to pause the resource.

Step 4: Narrow the question

The conversation carries context, so follow up in your own words rather than restating the whole question. Questions the skill handles well:

List the control planes and group them by phase.

List the unhealthy resources in prod-1, with the reason for each.

What CRDs and XRDs exist for AWS?

What changed in the last hour?

Two habits make the answers better. Name the control plane, realm or kind you care about, because a question with no scope leaves the agent to choose one for you. And ask for the reason alongside the count: condition messages are filterable, so the same question that returns a count of three can tell you which three and why.

Step 5: Check what the agent ran

The agent reports what it found without showing how it got there, so an answer you plan to act on is worth a second look.

1. Ask the agent to show its work.

   What endpoint did you call to get that?

   It should name a script or a Hub API path. That tells you the scope it queried, which is where a plausible wrong answer tends to originate.

2. Reproduce the query yourself when the answer matters.

   The same data comes straight from the API. See Query your fleet for the endpoints and the CEL filter syntax.

3. Check the age of the data before trusting an absence.

   Hub's view lags its sources, so a resource created moments ago may not appear yet. Each resources record carries hub.lastSyncTime, and the agent should check it against the clock before telling you something doesn't exist. Hub's own objects, such as control planes, spaces and realms, carry no such freshness field.

Step 6: Know where querying stops

Every step so far reads. Hub serves the fleet resources Insights aggregates as read-only, so asking the agent to fix a failing resource gets you a diagnosis rather than a change, and making the change means working in the control plane that owns the resource.

Hub's own objects are a different matter. The skill can create and delete control planes, realms, spaces and lenses, and update control planes and lenses. Neither realms nor spaces has an update verb. What the agent can change covers that along with the permissions and quirks that come with each.

Troubleshooting

Symptom	Cause
The agent asks for a Hub API endpoint	The skill has no endpoint for this machine yet. Give it the base URL of hub-core. It asks once.
Sign-in opens again, or calls start failing after about 90 days	The credential expired. Complete the browser sign-in and the agent continues.
Certificate or TLS verification errors	Your system trust store doesn't include Hub's CA. Set HUB_CA_FILE to a PEM bundle. Don't reach for HUB_INSECURE=1.
A resource you just created doesn't appear	Hub hasn't synced it yet. Check hub.lastSyncTime and ask again.
A count stops at 1000	The agent paged a list to count instead of using the aggregation endpoint. Ask which endpoint it called.
Two questions return different totals for the same thing	Type definitions and resource stats disagree by design, partly because composition fans one logical resource out into several records. Ask for both numbers.

See also

• Agent skills
• Query your fleet
• Resource filtering
• Insights